Conventionally, when measuring an ignition temperature of flammable liquid used as fuel, the so-called ASTM method (American Standard of Testing Method) is used widely. However, in the ASTM method (ASTM D2155-66, ASTM E659-79), since a combustion space is large, measurement errors become large.
On the other hand, in Patent Document 1, a method is proposed, the method of combusting fuel inside a tube to which a temperature gradient in the longitudinal direction thereof is applied, thereby forming flames therein, and of measuring an ignition temperature of the fuel based on the positions of the flames.